So, we can use some logical/math to make some conclusions…
1/60 stands for 1 thumb at each 60 seconds, the same as say each minute…
1/600 stands for 1 thumb at each 60 seconds * 10, the same as say each 10 minutes…

if we want a thumb at each 2 minutes we should multiply the 60 per 2, that will gives us 1/120… this way we can also assume that if we want a thumb at each 4 seconds, we can use 1/4.